Skanda's Companions and the Group of Mothers
Markandeya narrates the origin of Skanda's terrifying companions — sons and daughters born when the vajra struck him. The mothers of the world approach Skanda and ask to be made supreme, worshipped by all. He grants their wish, and through his favour, each mother bears a terrible son named Shishu, establishing the group of eight brave ones and the nine including Bhadrashakha.
Markandeya said: Now hear about Skanda's companions.
They were terrible and extraordinary. They were born when Skanda was struck by the vajra — the divine thunderbolt — and they are the minor Kumaras. These terrible ones steal children, whether they have already been born or whether they are still in the womb. From the force of the vajra, immensely strong daughters were also born from him.
The Kumaras thought of Vishakha as their father. The illustrious one protects in battle, with the face of a goat. He is surrounded by the masses of daughters and all his own sons. While the mothers look on, Bhadrashakha provides succour. So people on earth call Skanda the father of sons. In different regions, those who wish for sons or who already have sons always worship Rudra, Agni, and the extremely strong Uma as Svaha.
The maidens whom the fire named Tapas had begotten went to Skanda. He asked them: "What will I do?"
The mothers replied: "Grant us this favour. May we be the supreme mothers of all the worlds. May we be worshipped. Do this for our pleasure."
He replied that it would be this way. Then that great-souled one again said: "You will be of different kinds — auspicious and inauspicious."
Thus, having fulfilled the resolution of making Skanda their son, the group of mothers went away. Kaki, Halima, Rudra, Brihali, Arya, Palala, and Mitra became the seven mothers of children who have just been born. Through Skanda's favours, each of them had a terrible son, named Shishu — full of valour and red in the eye.
Those who were born from Skanda's group of mothers are known as the eight brave ones. Together with the one who has the face of a goat, they are referred to as the nine. Know that the sixth of Skanda's six heads has the face of a goat and is always worshipped by the group of mothers. The chief among his six heads is known as Bhadrashakha. It is through this that he created divine energy.
All these incidents occurred on the fifth day of shuklapaksha — the bright fortnight of the lunar month. O lord of men! The extremely terrible war transpired on the sixth. Aranyaka Parva, Chapter 514